72 



nion among the fishermen of the Zuiderzee that this happens in 

 cousequence of the coldness of the water. The question to 

 settle , if possible , is the foUowing : must these autumn-herrings 

 be considered as fore-runners of those herrings which next spring 

 will enter the Zuiderzee, or do they belong to another race ? Has 

 the Zuiderzee its autumn- and its spring-herrings as the Baltic 

 has, or is there no reason to distinguish two Zuiderzee-races? 



Of late I have had again a fair opportunity off investigating a 

 number of true Zuiderzee-autumn-herrings. I then measured and 

 calculated the formulae of 120 herrings caught in autumn in the 

 Zuiderzee , or at the entrance to that sea betweeu Helder and Texel : 

 this number proved quite sufiBcient to show the very near rela- 

 tion of these herrings with the spring-herrings of the Zuiderzee. 

 This may be best judged by comparing the foUowing table, from 

 which purposely those are omitted which were only encountered 

 once, with the table of p. 69. 



Of the remaining 16 a few show a quite extravagant for- 

 mula; thus 2d IIC, 2d IIB, 3d III C aud 4d IV C ; some 

 have the combination of peculiar features characteristic of the 

 true Northsea-herrings : la IA, la IB, 2a IIB, 2a IIC gi- 

 ving, combined with those entered in the above list: Ib I B (2), 

 Ib IIB (2), Ib IIC (3) and 2 a I A (2) , in all 13 of the 120 

 or IP/oi which might represent the Northsea-race under the au- 

 tumn-herrings, a number even smaller thau that found for the 



